More than 21,000 army officers and intellectuals were executed at Katyn

The Polish parliament has called on Moscow to publish the names of any surviving perpetrators of a World War II massacre.

Members of parliament passed a resolution demanding the killing of thousands of Polish soldiers in the Katyn Forest be recognised as genocide.

Moscow only took responsibility for the killings in 1990, after previously blaming it on the Nazis.

Polish legislators stood for a minute's silence before passing the resolution.

Members of the victims' families were also present to mark the 65th anniversary of the massacre.

Classified files

The resolution stated that only a full disclosure of the truth and a condemnation of the perpetrators could lead to improved relations between Poland and Russia.

Moscow ended a lengthy inquiry into the crime last year, which concluded the killings were not genocide. Poland then set up its own investigation, but Moscow has refused to hand over many files which are still classified.

Both Nazi Germany and the Soviet Union invaded Poland at the start of World War II.

The Soviet secret police arrested millions of Poles. Many of them ended up in Siberian labour camps, but more than 21,000 army officers and intellectuals were executed on Stalin's direct orders in the Katyn Forest near the city of Smolensk.

The Nazis discovered the mass graves in 1943, but Moscow only admitted Soviet guilt 47 years later.